In this entry, which is part of the forthcoming Encyclopedia of Private International Law (edited by Jürgen Basedow, Franco Ferrari, Pedro de Miguel Asensio, & Giesela Rühl, Edward Elgar, forthcoming 2017), I explore correlations between domestic regimes of private international law and World Trade Organization (WTO) law. Both sectors have traditionally been viewed as separate areas. Private international law (particularly choice of law) is viewed as part of a country’s national law. It is limited largely to private-party disputes and, hence, individual interests. WTO law, by contrast, is seen as a segment of public international law, an area to be kept strictly separate from national law. Private parties are neither directly protected nor endowed with individual rights. As can be shown, this impression of isolation is incorrect, primarily because private international law is no longer limited (if it ever was) to the resolution of private-party conflicts. It is the modern ‘regulatory function’ of private international law that may conflict with a state’s obligations under public international law. This becomes a concern with respect to WTO law.